Each dish consists of traditional vinegared rice topped with a slice of grilled freshwater eel. That’s then crowned with a pat of butter held in place by a little strip of seaweed. The heat from the eel softens the butter just enough to make it creamy, and fans say it makes the sushi feel like it is melting in their mouths.

Butter and sushi seems like an odd pairing, but it is evidently catching on pretty well. It seems inevitable that it will branch out and start appearing on other sushi restaurant menus soon.